1. Field of the Invention
This invention relates to voice or sound recognition technology, and, in particular, to a voice recognition system and method for recognizing an unknown voice using a voice power pattern.
2. Description of the Prior Art
Voice recognition technology has drawn much attention recently for applications to various office machines and the like. It has been developed to the extent that it can now recognize not only spoken words, but also monosyllabic voices or sounds. There has been proposed a voice recognition system using binary processing for ease of voice recognition. In accordance with this prior art method, a voice input is processed through a plurality of band-pass filters different in frequency range to obtain a time-frequency distribution pattern which is then compared with each of the previously stored patterns, whereby the degree of similarity between the input pattern and each of the stored patterns is determined. As a result, the one of the stored patterns which has the highest degree of similarity is chosen to identify the unknown voice thus input. In this system, the time-frequency distribution pattern can be represented by the binary numbers, and, thus, the processing of such binary-valued patterns can be carried out at high speed and with high reliability.
However, in accordance with the above-described prior art system, information relating to the intensity level or magnitude of voice is lost, so that it can recognize sounds abundant in information, such as words and speeches, with high reliability; however, it has difficulty in recognizing relatively short voices and sounds, such as monosyllabic sounds. For example, the prior art methods often encounter difficulty in recognizing the differences between such sounds as "P" and "K." Thus, there has been a need to develop a new technology which can recognize even relatively short voices or sounds which are rather scarce in sound information at high accuracy.